Negative thermal expansion,electrical and mechanical properties of antiperovskite Mn3Zn0.5A0.5N (A?=?Sn,Ag, Ni)

Thermal expansion, electrical conductivity, hardness and friction property of Mn₃ZnN, which had been doped with Sn, Ag or Ni and sintered at 1223?K, were measured. X-ray diffraction analyses show that these compounds have a cubic antiperovskite Mn₃CuN-type structure and negative thermal expansion (NTE). The width of NTE operation temperature (ΔT) and the coefficient of thermal expansion are different when Mn₃ZnN was doped with different element. A giant NTE coefficient of ?81.00?×?10^?6?K^?1 is obtained from Mn₃Zn_0.5Ag_0.5N while ΔT is 18?K. A broad ΔT of 60?K is obtained from Mn₃Zn_0.5Sn_0.5N with thermal expansion coefficient of ?19.05?×?10^?6?K^?1. The results show that Mn₃Zn_0.5 A_0.5N (A?=?Sn, Ag, Ni) has good electrical conductivity. The electrical conductivity of Mn₃Zn_0.5Ag_0.5N is the largest among these compounds as 2.45?×?10³?S?cm^?1. The Vickers hardness of these compounds is more than 350?HV. The friction coefficients of Mn₃Zn_0.5Ag_0.5N, Mn₃Zn_0.5Ni_0.5N and Mn₃Zn_0.5Sn_0.5N are 0.5318, 0.4554 and 0.2336, respectively.